From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6E95BC34034 for ; Tue, 18 Feb 2020 07:03:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 461822176D for ; Tue, 18 Feb 2020 07:03:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726399AbgBRHDQ (ORCPT ); Tue, 18 Feb 2020 02:03:16 -0500 Received: from metis.ext.pengutronix.de ([85.220.165.71]:48427 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726104AbgBRHDQ (ORCPT ); Tue, 18 Feb 2020 02:03:16 -0500 Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1j3wuV-0007Ym-Hi; Tue, 18 Feb 2020 08:03:11 +0100 Received: from ukl by ptx.hi.pengutronix.de with local (Exim 4.89) (envelope-from ) id 1j3wuU-0005OG-LI; Tue, 18 Feb 2020 08:03:10 +0100 Date: Tue, 18 Feb 2020 08:03:10 +0100 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= To: "gregkh@linuxfoundation.org" Cc: Schrempf Frieder , "stable@vger.kernel.org" , "shawnguo@kernel.org" , "linux-kernel@vger.kernel.org" , "linux-serial@vger.kernel.org" Subject: Re: [PATCH 0/2] serial: imx: Backport fixes for irq handling to v4.14 Message-ID: <20200218070310.ibv2m2f7ihfaevrp@pengutronix.de> References: <20200217140740.29743-1-frieder.schrempf@kontron.de> <20200218045008.GA2049358@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20200218045008.GA2049358@kroah.com> User-Agent: NeoMutt/20170113 (1.7.2) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 18, 2020 at 05:50:08AM +0100, gregkh@linuxfoundation.org wrote: > On Mon, Feb 17, 2020 at 02:08:00PM +0000, Schrempf Frieder wrote: > > From: Frieder Schrempf > > > > A customer of ours has problems with RS485 on i.MX6UL with the latest v4.14 > > kernel. They get an exception like below from time to time (the trace is > > from an older kernel, but the problem also exists in v4.14.170). > > > > As the cpuidle state 2 causes large delays for the interrupt that controls the > > RS485 RTS signal (which can lead to collisions on the bus), cpuidle state 2 was > > disabled on this system. This aspect might cause the exception happening more > > often on this system than on other systems with default cpuidle settings. > > > > Looking for solutions I found Uwe's patches that were applied in v4.17 being > > mentioned here [1] and here [2]. In [1] Uwe notes that backporting these fixes > > to v4.14 might not be trivial, but I tried and in my opinion found it not to be > > too problematic either. > > > > With the backported patches applied, our customer reports that the exceptions > > stopped occuring. Given this and the fact that the problem seems to be known > > and quite common, it would be nice to get this into the v4.14 stable tree. > > Thanks for the backports, both now queued up. To complete these fixes you also want to backport 101aa46bd221 serial: imx: fix a race condition in receive path Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ |